html,
body {
    padding: 0;
    margin: 0;
}

li {
    font-size: 12px;
    line-height: 30px;
}

.box {
    width: 600px;
    height: 400px;
    //默认webpack无法处理css中的url
    background: url('../images/timg.jpg');
    background-size: cover;
}